A cordless phone is a telephone where the two parts are separate and not joined by a curly cord like some telephones are. The main bit, called the base, is plugged into the wall and it is where the calls come in.
Each call then gets sent in radio waves in the air to a handset with buttons and places to speak and listen.
Cordless phones have only been around for a short time, but with some cordless phones the handset can be moved 100 metres away from where the base is.
The telephone is something that people use to talk to others that are not near by. You can speak to almost anyone around the world with a telephone.
A guy called Alexander Bell invented a very simple machine in 1876 that was the very first telephone. Since then, people have made changes to the telephone until it was like it is now.
The telephone is very amazing. When you speak into it, the telephone changes your voice into an electrical signal so it can travel through the phone lines and underground phone cables. The electrical signal is then turned back into your voice at the phone of the person you are talking too. If you are talking to someone who is a long distance away, like a country on the other side of the world, your voice travels as an electronic signal through undersea cables and is bounced off satellites in space like bouncing a basketball against the ground!
A mobile phone is a phone that can be taken almost anywhere. In the last couple of years mobile phones have become smaller and smaller!
Mobile phones can do heaps of things. Some mobile phones can be used to send short-word text messages, take photographs which you can send to friends as picture messages, do things that you do on a computer and keep a diary of appointments and meetings.
A mobile phone turns your message or your voice into radio waves which travel through the air to tall transmitters. These transmitters take you message to computers which will send the message to the person you have sent it to or the person you are talking to.
In many countries there are mobile phone transmitters in every town and suburb.